Chainsaw files are very important as they can help prolong the lifespan of your chainsaw chain. Cutting with dull chains leads to a higher fuel consumption as well as excessive wear on the chainsaw so it is important to always use sharp chains. Instead of replacing the chain when it becomes dull and blunt, you can use a file to sharpen the cutting teeth, therefore improving the efficiency of the chainsaw.
However not every chainsaw chain is created equal and choosing the right chainsaw file is paramount, as it needs to match your chain; choosing the wrong file will diminish the cutting performance from the chainsaw chain. To be absolutely sure what type of chainsaw file you need for your chain you should check your manufacturers manual.